Slurry feeder



March 17, 1959 J. R. [Rl-:LAND

SLURRY FEEDER Filed June 6, 1956 SLURRY FEEDER Application June 6, 1956,serial No. 589,606 6 claims. (ci. zzz- 1) The present invention relatesto an apparatus and method for handling slurries of the type which tendto settle out on standing, even when the standing time is relativelyshort` The present invention is applicable generally to the handling ofslurries of any composition provided that the slurry is suficientlyliquid to flow through orifices and through piping. The presentinvention is particularly applicable to the handling of alkaline earthcompounds in admixture with iron oxides suspended in Water. Suchslurries are employed in the manufacture of pressed magnets of theceramic type. Heretofore, considerable difficulty has been encounteredin providing a feeding system to introduce such slurries into moldingdies in exactly the quantities required because of the tendency of thesolid material in the slurry to settle out in piping and in storagecontainers.

An object of the present invention is to provide an improved slurryhandling system arranged to deliver predetermined, controlled amounts ofthe` slurry to a container such as a shaping die.

Another object of the invention is to provide an improved slurryhandling system in which the slurry is kept in a state of constantagitation even though the molding dies are to be filled onlyperiodically.

Another object of the invention is to provide an irnproved method forhandling slurries in a die filling process which minimizes or completelyeliminates the settling problem.

A further description of the present invention will be made inconjunction with the attached sheet of drawings in which:

Figure 1 is a schematic view of a slurry handling system according tothe present invention illustrating the position of the elements near thecompletion of the discharge cycle; and

Figure 2 is a view similar to Figure 1 but illustrating the condition atthe end of the filling cycle.

As shown in the drawings:

In Figure 1, reference numeral indicates generally a container orreservoir for storing the bulk of the slurry in the system. A body 11 ofthe slurry is kept in a coustant state of agitation by means of anagitator 12 driven by a suitable motor 13.

The container 10 has an outlet line 14 which continuously feeds slurryby gravity from the container 10 to a continuously operating slurry pump16 of any suitable design. The discharge of the pump 16 is directed intoa conduit 17 from which it is selectively directed either into a bypassline i8 or a feed line 19 associated with a feeding mechanism forfilling the containers or molding dies with the slurry.

The particular feeding mechanisms illustrated in the drawings are of thepositive displacement type and include one or more piston type feeders21 and 22. As illustrated, the feeder 21 includes a cylinder 23providing a pumping chamber and a reciprocating piston 24 having astroke dependent upon the exact amount of slurry nited States Patentf'ce which is to be delivered to the container or molding die to .befilled. Similarly, the feeder 22 includes a cylinder 26 providing apumping chamber and a piston 27 for the same purpose. Obviously, themovement of the pistons 24 and 27 can be tied together mechanically ifso desired.

The inlet to the feed mechanisms is controlled by the operation of avalve 28 in the inlet to the feed mechanisms, and an outlet valve 29 atthe discharge end of the feed mechanisms. The valve 29 is located in anoverflow line 31 which directs overflow from the feeding operation backinto the container 10 as will be more apparent from a succeeding portionof this description.

The slurries are discharged under pressure by the operation ofthepistons 24 and 27 to the respective outlet lines 33 and 34, the flowthrough the outlet lines being governed by the operation of a pair ofvalves 36 and 37 as illustrated.

A valve 38 is located in the bypass line 18 to permit continuouscirculation of the slurry, even when the feed mechanisms aredischarging, so as to avoid the possibility of settling in the lineswhile the 'feed mechanisms are discharging.

It is important for the purposes of this invention that the system bekept full of slurry at all times to avoid the possibility of airentrainment in the slurry.

As illustrated in Figure l, during the discharge cycle of the apparatus,the Valve 38 is open, permitting circulation of the slurry from thecontinuously operating pump 16 back into the container 10. During thiscycle, the valves 2S and 29 are closed and the pistons 24 and 27 of thefeed mechanisms force the slurry contained in the cylinders 23 and 26under pressure through their respective discharge outlets 33 and 34, thevalves 36 and 37 being open to permit this discharge. The dashed lines40 in Figure 1 represent the inward limit of travel of the pistons 24and 27 in their respective cylinders. At the completion of the dischargecycle the valves 36 and 37 are closed, the valves 28 and 29 are open,and the valve 38 is closed, as illustrated in Figure 2. The continuouslyoperating pump 16 thereupon supplies the slurry under pressure to theline 19 and into the cylinders 23 and 26. During the filling cycle, ofcourse, the pistons 24 and 27 are moved to the left, as viewed inFigures 1 and 2, under the pressure of the slurry from the operatingpump 16 until the cylinders 23 and 26 are filled to the required amount.The slurry is thereby injected into the feed mechanisms without theaccumulation of any air therein, since the slurry is being introducedunder pressure at all times and the cylinders are full of slurry at alltimes. When the cylinders 23 and 26 are filled to the required extent,the slurry overflows through the line 31, since the valve 29 is open,and the overflow is recirculated back into the container 10. In thisway, the slurry is kept in continuous motion until such time as the nextdischarge cycle is to occur. At that time the valves 28 and 29 areclosed, and the valves 36, 37 and 38 are another discharge cycle.

While the system has been shown in a somewhat simplified form, it willbe recognized that the valves and pistons can be operated hydraulically,pneumatically, or by any suitable mechanical means in the desiredsequence.

A system of the type described has been used successfully in the feedingof rapidly settable slurries. The system is very economical to operateand has a low initial cost and upkeep. Since the entire feed side of thesystem is at all times filled with slurry up to its operating volumecapacity, there is no chance for air to get into the feed side of thesystem.

It will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention.

opened, starting I claim as my invention:

1. A slurry feeding system comprising a storage means for receiving aslurry, a pump receiving slurry from said storage means, a feeding meanshaving a pumping chamber, a bypass means upstream of said pumpingchamber and ,discharging into said storage means, valve means arrangedto direct selectively the discharge of said pump into and through saidfeeding means or into said bypass means, and means directing materialpassing through said feeding means back into said storage means, saidsystem constituting a closed circuit for the circulation of said slurry.

2. A closed circuit slurry feeding system comprising storage means forreceiving a slurry, a pump receiving slurry from said storage means, apositive displacement feeding means including a pressure chamberreceiving the discharge from said pump, a first conduit means forwithdrawing the discharge from said pressure chamber during pressuredischarge from said feeding means, a second conduit for recirculatingmaterial from said pressure chamber back into said storage means whilesaid feeding means is not discharging, and a bypass system selectivelyreceiving the discharge of said pump in advance of said feeding meansand arranged to direct the discharge of said pump back into said storagemeans.

3. A slurry feeding system comprising storage means for receiving aslurry, a pump receiving slurry from said storage means, a bypass meansconnected to the discharge end of said pump and arranged to circulateslurry back into said storage means, a feed means connected to thedischarge end of said pump downstream of said by-passmeans, valve meansfor selectively directing the discharge of said pump into said bypassmeans or into said feed means, outlet means for discharging slurry fromsaid feed means under pressure, valve means associated with said outletmeans for controlling discharge through said out,`

let means, venting means for withdrawing slurry from said feed meanswhile said feed means is not discharging and for returning slurry tosaid storage means, and valvel means for closing said Venting meansduring the filling of said feed means.

4. A slurry feeding system comprising storage means for receiving alslurry, a constantly operating pump receiving slurry from said storagemeans, a feed means connected to the discharge end of said pump, saidfeed means being arranged to have a discharge cycle and a filling cycle,a bypass means connected to the discharge end of said pump upstream ofsaid feed means, valve means selectively operable to direct thedischarge from said pump into said feed means or into said bypass means,means for withdrawing slurry from said feed means during its dischargecycle, and means for recirculating slurry from said feed means back tosaid storage means during said filling cycle of said feed means.

5. A slurry feeding system comprising storage means for receiving aslurry, a constantly operating pump receiving slurry from said storagemeans, a piston type feed means having a filling cycle and a dischargecycle connected to the discharge end of said pump, a by-pass meansupstream of said feed means arranged to direct slurry from said pump tosaid storage means, valve means for selectively directing the dischargeof said pump into said bypass means or into said feed means, outletmeans for withdrawing slurry from said feed means during its dischargecycle, and means for recirculating slurry back into said storage meansduring said filling cycle of said feed means.

6. The method of feeding a slurry having a tendency to settle outparticles which comprises continuously pumping said slurry from astorage means into a positive displacement feed means to iill said feedmeans, continuing the iiow through said feed means after filling anddirecting the overflow from said feed means into said storage means,periodically terminating the iiow into said feed means while by-passingflow from said storage means back into said storage means, anddischarging slurry from said feed means during such periodictermination.

References Cited in the file of this patent UNITED STATES PATENTS1,579,434 Brombaker Apr. 6, 1926 2,364,264 Yeomans Dec. 5, 19442,646,190 Hensgen et al. July 21, 1953

